This year we have again been involved in many projects relating to the analysis of peptides and proteins. Among many others these include the nature of the inhibition of peptidyl glycine hydroxylating monooxygenase, determination of the site of phosphorylation of a chemokine receptor, detection of glutathonylation of an actin fragment, detection of a ca. 250 moleclar weight endogenous aldose reductase inhibitor, developed a GC/MS approach to analysis of oleamide and andanamide using a new constant neutral loss mass spectrometry, identified phosphorylation sites in light chain myosin involved in the " stretch activation" response essential to the generation of oscillatory power in the beating heart, an EGFR mitogenic signal transducer which becomes hyperphosphorylated upon EGF stimulation. We are also working on a new system to identify protein structures by linking external amino groups with deuterated chains.